Integrated structures including material containing silicon, nitrogen, and at least one of carbon, oxygen, boron and phosphorus

ABSTRACT

Some embodiments include an integrated structure having vertically-stacked conductive levels alternating with dielectric levels. A layer over the conductive levels includes silicon, nitrogen, and one or more of carbon, oxygen, boron and phosphorus. In some embodiments the vertically-stacked conductive levels are wordline levels within a NAND memory array. Some embodiments include an integrated structure having vertically-stacked conductive levels alternating with dielectric levels. Vertically-stacked NAND memory cells are along the conductive levels within a memory array region. A staircase region is proximate the memory array region. The staircase region has electrical contacts in one-to-one correspondence with the conductive levels. A layer is over the memory array region and over the staircase region. The layer includes silicon, nitrogen, and one or more of carbon, oxygen, boron and phosphorus.

RELATED PATENT DATA

This patent resulted from a continuation of U.S. patent application Ser.No. 15/133,119 filed Apr. 19, 2016, which is incorporated by referenceherein.

TECHNICAL FIELD

Integrated structures including material containing silicon, nitrogen,and at least one of carbon, oxygen, boron and phosphorus.

BACKGROUND

Memory provides data storage for electronic systems. Flash memory is onetype of memory, and has numerous uses in modern computers and devices.For instance, modern personal computers may have BIOS stored on a flashmemory chip. As another example, it is becoming increasingly common forcomputers and other devices to utilize flash memory in solid statedrives to replace conventional hard drives. As yet another example,flash memory is popular in wireless electronic devices because itenables manufacturers to support new communication protocols as theybecome standardized, and to provide the ability to remotely upgrade thedevices for enhanced features.

NAND may be a basic architecture of integrated flash memory. A NAND cellunit comprises at least one selecting device coupled in series to aserial combination of memory cells (with the serial combination commonlybeing referred to as a NAND string). NAND architecture may be configuredto comprise vertically-stacked memory cells. It is desired to developimproved NAND architecture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic cross-sectional view illustrating regions of anintegrated construction at a processing stage of an example embodiment.

FIG. 2 is a diagrammatic cross-sectional view illustrating the regionsof FIG. 1 at an example embodiment processing stage subsequent to thatof FIG. 1.

FIG. 3 is a diagrammatic cross-sectional view illustrating regionssimilar to those of FIG. 1 at another example embodiment processingstage subsequent to that of FIG. 1.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Some embodiments include integrated circuit constructions having amaterial containing silicon, nitrogen and at least one of carbon,oxygen, boron and phosphorus. The material may extend across a memoryarray region. In some embodiments the memory array region comprisesvertically-stacked wordline levels which extend to a staircase region(also sometimes referred to as a stepped region, shark jaw region, etc.)where conductive contacts are extended to individual wordline levels. Insome embodiments the material may extend across one or both of thememory array region and the staircase region. The material may providenumerous advantages. For instance, the material may provide aninsulative barrier to protect underlying conductive levels in the eventof mask misalignment during fabrication of conductive contacts toregions over and/or near the conductive levels. As another example, thematerial may be fabricated to have compressive/tensile stress propertieswhich compensate for stresses of underlying materials to alleviatebending and/or other undesired contortion of an integrated circuit die.Example embodiments are described with reference to FIGS. 1-3.

Referring to FIG. 1, portions of a construction 10 are illustrated, withsuch portions corresponding to integrated structures. One of theportions is a fragment of a memory array region 12 and the other is afragment of a staircase region 14.

A stack 15 of alternating levels 18 and 20 extends across the regions 12and 14. The levels 18 may comprise dielectric material, such as, forexample, silicon dioxide. The levels 20 may comprise sacrificial (i.e.,replaceable) material, such as, for example, silicon nitride. The levels18 and 20 may have any suitable thicknesses. The levels 18 and 20 may bethe same thickness as one another in some embodiments, and may differ inthickness relative to one another in other embodiments.

An insulative region 22 is over the uppermost level 20. Such insulativeregion may comprise any suitable insulative composition or combinationof insulative compositions; including, for example, silicon dioxide.Although the region 22 is shown to comprise a single homogeneouscomposition, in other embodiments the region 22 may comprise two or morediscrete compositions.

A layer 26 is over the insulative region 22, and such layer is composedof a material 24. Material 24 comprises silicon, nitrogen and one ormore substances selected from the group consisting of carbon, oxygen,boron and phosphorus. In some embodiments a total concentration ofcarbon, oxygen, boron and/or phosphorus within material 24 is at leastabout 2 atomic percent, at least about 4 atomic percent, at least about10 atomic percent, etc. In some embodiments a total concentration ofcarbon, oxygen, boron and/or phosphorus within the material 24 is withina range of from about 2 atomic percent to about 20 atomic percent;within a range of from about 6 atomic percent to about 11 atomicpercent, etc. In some embodiments, the material 24 may consist ofsilicon, nitrogen and one or more of carbon, oxygen, boron andphosphorus.

An advantage of including carbon, oxygen, boron and/or phosphorus withinthe silicon nitride material 24 is that such can render material 24resistant to etching subsequently utilized to remove sacrificial siliconnitride within levels 20 (discussed below with reference to FIG. 2).Accordingly, it can be desired that the total concentration of carbon,oxygen, boron and/or phosphorus within silicon nitride material 24 besufficient to render the material 24 resistant to the etch utilized toremove silicon nitride (or other suitable replaceable material) withinlevels 20. It can also be desired that material 24 be nonconductive.Accordingly, it can be desired that the concentration of substancesincluded within the silicon nitride of material 24 (for instance,carbon) be kept low enough so that the silicon nitride material 24remains nonconductive. The silicon nitride material 24 may be referredto as an “enhanced silicon nitride material” to indicate that thesilicon nitride material comprises a composition tailored for advantagesrelative to silicon nitride alone.

Patterned material 28 is provided over the enhanced silicon nitridematerial 24. The patterned material 28 may comprise any suitablecomposition or combination of compositions, and in some embodiments willcomprise dielectric material, such as, for example, silicon dioxide.

Dots are provided above and below the illustrated portions ofconstruction 10 to indicate that there may be multiple additional levelsor other structures above and below the illustrated portions. Also, dotsare provided at the lower end of the bracket illustrating stack 15 toindicate that the stack may extend below the illustrated portion. Aselect gate level, source line, etc., may be below the illustratedportions of construction 10 in some embodiments.

In some embodiments the illustrated portions of construction 10 would besupported by a semiconductor substrate; which may, for example,comprise, consist essentially of, or consist of monocrystalline silicon.The term “semiconductor substrate” means any construction comprisingsemiconductive material, including, but not limited to, bulksemiconductive materials such as a semiconductive wafer (either alone orin assemblies comprising other materials), and semiconductive materiallayers (either alone or in assemblies comprising other materials). Theterm “substrate” refers to any supporting structure, including, but notlimited to, the semiconductor substrates described above.

First and second openings 30 and 32 extend through stack 15 withinmemory array region 12.

The first opening 30 represents one of a plurality of slits utilized tosubdivide a memory array into programmable blocks. In some embodimentsthe individual blocks may correspond to smallest units within the memoryarray which may be erased, and each block may contain a number of pageswhich correspond to the smallest units which may be programmed.

The second opening 32 represents a region where vertically-stackedmemory cells are formed. Channel material 34 is within opening 32, andis spaced from materials of stack 15 by dielectric material 36,charge-storage material 38 and charge-blocking material 40. Thematerials 34, 36, 38 and 40 may comprise any suitable compositions orcombinations of compositions. For instance, channel material 34 maycomprise appropriately-doped silicon; dielectric material 36 maycomprise one or more of silicon dioxide, hafnium oxide, aluminum oxide,zirconium oxide, etc.; charge-storage material 38 may comprise one ormore charge-trapping materials, such as silicon nitride, siliconoxynitride, metal dots, etc.; and charge-blocking material 40 maycomprise one or more of silicon dioxide, aluminum oxide, hafnium oxide,zirconium oxide, etc.

The illustrated channel material 34 lines sidewalls of opening 32 toleave a central region filled with dielectric material 42. Suchcorresponds to a so-called hollow channel configuration. In otherembodiments the channel material may fill a central region of opening 32as a solid pillar. The dielectric material 42 may comprise any suitablecomposition, such as, for example, oxide (e.g., silicon dioxide).

A conductive plug 48 is provided over dielectric material 42. Theconductive plug 48 may comprise any suitable composition or combinationof compositions; including, for example, one or more ofconductively-doped semiconductor material (for instance,conductively-doped silicon, conductively-doped germanium, etc.), metal(for instance, tungsten, titanium, etc.), and metal-containingcompositions (for instance, metal nitride, metal carbide, etc.).

The first and second openings 30 and 32, and the structures withinopening 32, are representative of numerous openings and structures thatmay be formed across a memory array.

First, second and third openings 44-46 extend through various materialsof the staircase region 14. Each opening extends to a different one ofthe levels 20, and ultimately is utilized to form an electrical contactextending to the exposed level. Dielectric material 48 is providedwithin the staircase region adjacent pedestals comprising thealternating levels 18 and 20. The dielectric material 48 may compriseany suitable composition or combination of compositions, including, forexample, oxide (such as silicon dioxide).

All of the openings 30, 32 and 44-46 are shown formed at a commonprocessing stage in FIG. 1 in order to simplify description ofadvantages of the enhanced silicon nitride material 24. In practice, oneor more of the openings 30, 32 and 44-46 may be formed at a differentprocessing stage relative to others of the openings.

Referring to FIG. 2, the sacrificial material of levels 20 (FIG. 1) isremoved and replaced by conductive material to form conductive levels50. The conductive material of levels 50 may comprise any suitablecomposition or combination of compositions; and may, for example,comprise, consist essentially of, or consist of one or more ofconductively-doped semiconductor material(s), metal(s), ormetal-containing composition(s). In some embodiments, the conductivematerial of levels 50 may comprise, consist essentially of, or consistof tantalum or tungsten.

Conductive levels 50 may be referred to as vertically-stacked conductivelevels which alternate with dielectric levels 18. In some embodiments,the conductive levels 50 may be referred to as vertically-stacked NANDwordline levels.

A NAND memory array may be formed across the memory array region 12.Such NAND memory array comprises vertically-stacked memory cells, withsome example memory cells 52 being diagrammatically illustrated in FIG.2. The memory cells comprise regions of conductive levels 50 as controlgate material, and comprise regions of the channel material 34,dielectric material 36, charge-storage material 38 and charge-blockingmaterial 40.

Conductive interconnects 54-56 are formed within the openings 44-46across staircase region 14. The conductive interconnects 54-56 are inone-to-one correspondence with the conductive levels (i.e. wordlinelevels) 50 and connect specific wordline levels with other circuitry(not shown). Such other circuitry may be utilized to, for example,trigger specific wordline levels during programming, erasing and/orreading operations. The conductive interconnects 54-56 may comprise anysuitable electrically conductive compositions or combinations ofcompositions; and may, for example, comprise, consist essentially of, orconsist of one or more of conductively-doped semiconductor material(s),metal(s), or metal-containing composition(s).

The enhanced silicon nitride material 24 extends across the memory cells52 of the NAND memory array, and also extends across the staircaseregion 14. The enhanced silicon nitride material 24 remains afterreplacement of silicon nitride of levels 20 (FIG. 1) due to theincorporation of one or more of carbon, oxygen, boron and phosphoruswithin the enhanced silicon nitride material. The enhanced siliconnitride material 24 may advantageously provide compressive/tensilestress characteristics which balance the stresses of underlyingmaterials to enhance planarity of an integrated circuit die relative toa conventional die lacking enhanced silicon nitride material 24.Further, relative amounts of carbon, oxygen, boron and/or phosphoruswithin the enhanced silicon nitride material 24 may be tailored toachieve tensile/compressive stress characteristics suitable for specificapplications.

In the illustrated embodiment, the enhanced silicon nitride material 24is spaced from an uppermost conductive level 50 by only the singledielectric region 22. Such may simplify processing as compared to otherconstructions in which enhanced silicon nitride material 24 is spacedfrom the uppermost conductive level by additional materials.

A conductive interconnect 58 is shown provided within opening 32 toelectrically connect with channel material 34 and conductive plug 48.Such interconnect may electrically connect the channel material 34 withother circuitry (not shown). The interconnect 58 may comprise anysuitable electrically conductive composition or combination ofcompositions; and may, for example, comprise, consist essentially of, orconsist of one or more of conductively-doped semiconductor material(s),metal(s), or metal-containing composition(s).

In the illustrated embodiment of FIG. 2, the interconnect 58 isappropriately aligned with underlying materials. However, in someapplications there may be misalignment of the interconnect 58 due to,for example, misalignment of a mask utilized to pattern an opening forinterconnect 58. FIG. 3 shows a construction 10 a analogous to theconstruction of FIG. 2, but having the interconnect 58 misaligned.Advantageously, the enhanced silicon nitride material 24 protects theunderlying dielectric region 22 from being compromised during formationof the misaligned opening for interconnect 58, and thus avoids aproblematic short that could otherwise occur between the conductivematerial of interconnect 58 and the uppermost conductive level 50.

Although various embodiments are described above with reference to NANDarchitectures, it is to be understood that aspects of the invention(s)described herein may extend to architectures other than NAND. Such otherarchitectures may include memory architectures, logic architectures,etc.

The constructions discussed above may be incorporated into electronicsystems. Such electronic systems may be used in, for example, memorymodules, device drivers, power modules, communication modems, processormodules, and application-specific modules, and may include multilayer,multichip modules. The electronic systems may be any of a broad range ofsystems, such as, for example, cameras, wireless devices, displays, chipsets, set top boxes, games, lighting, vehicles, clocks, televisions,cell phones, personal computers, automobiles, industrial controlsystems, aircraft, etc.

Unless specified otherwise, the various materials, substances,compositions, etc. described herein may be formed with any suitablemethodologies, either now known or yet to be developed, including, forexample, atomic layer deposition (ALD), chemical vapor deposition (CVD),physical vapor deposition (PVD), etc.

Both of the terms “dielectric” and “electrically insulative” may beutilized to describe materials having insulative electrical properties.The terms are considered synonymous in this disclosure. The utilizationof the term “dielectric” in some instances, and the term “electricallyinsulative” in other instances, may be to provide language variationwithin this disclosure to simplify antecedent basis within the claimsthat follow, and is not utilized to indicate any significant chemical orelectrical differences.

The particular orientation of the various embodiments in the drawings isfor illustrative purposes only, and the embodiments may be rotatedrelative to the shown orientations in some applications. The descriptionprovided herein, and the claims that follow, pertain to any structuresthat have the described relationships between various features,regardless of whether the structures are in the particular orientationof the drawings, or are rotated relative to such orientation.

The cross-sectional views of the accompanying illustrations only showfeatures within the planes of the cross-sections, and do not showmaterials behind the planes of the cross-sections in order to simplifythe drawings.

When a structure is referred to above as being “on” or “against” anotherstructure, it can be directly on the other structure or interveningstructures may also be present. In contrast, when a structure isreferred to as being “directly on” or “directly against” anotherstructure, there are no intervening structures present. When a structureis referred to as being “connected” or “coupled” to another structure,it can be directly connected or coupled to the other structure, orintervening structures may be present. In contrast, when a structure isreferred to as being “directly connected” or “directly coupled” toanother structure, there are no intervening structures present.

Some embodiments include an integrated structure comprisingvertically-stacked conductive levels alternating with dielectric levels.A layer over the conductive levels comprises silicon, nitrogen, and oneor more substances selected from the group consisting of carbon, oxygen,boron and phosphorus; wherein a total concentration of said one or moresubstances is within a range of from about 2 atomic percent to about 20atomic percent.

Some embodiments include an integrated structure comprisingvertically-stacked NAND wordline levels within a NAND memory array. Alayer over the wordline levels comprises silicon, nitrogen, and one ormore substances selected from the group consisting of carbon, oxygen,boron and phosphorus; wherein a total concentration of said one or moresubstances is at least about 2 atomic percent. The layer is spaced froman uppermost of the wordline levels by no more than one insulativeregion.

Some embodiments include an integrated structure comprisingvertically-stacked conductive levels alternating with dielectric levels.Vertically-stacked NAND memory cells are along the conductive levelswithin a memory array region. A staircase region is proximate the memoryarray region. The staircase region comprises electrical contacts inone-to-one correspondence with the conductive levels. A layer is overthe memory array region and over the staircase region. The layercomprises silicon, nitrogen, and one or more substances selected fromthe group consisting of carbon, oxygen, boron and phosphorus; wherein atotal concentration of said one or more substances is within a range offrom about 2 atomic percent to about 20 atomic percent.

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

We claim:
 1. A method of forming an integrated structure, comprising:forming vertically-stacked NAND wordline levels within a NAND memoryarray, the wordline levels being vertically separated from one anotherby intervening dielectric levels that physically contact the wordlinelevels; forming a material over the wordline levels and spaced from anuppermost of the wordline levels by an insulative region, the materialbeing in direct physical contact with the insulative region, thematerial comprising silicon, nitrogen, and one or more substancesselected from the group consisting of carbon, oxygen, boron andphosphorus, a total concentration of said one or more substances beingpresent within a range of from about 2 atomic percent to about 20 atomicpercent; and forming at least one opening extending through the materialover the wordline levels and through at least some of the wordlinelevels.
 2. The integrated structure of claim 1 wherein said totalconcentration of the one or more substances is at least about 4 atomicpercent.
 3. The integrated structure of claim 1 wherein said totalconcentration of the one or more substances is at least about 10 atomicpercent.
 4. The integrated structure of claim 1 wherein said totalconcentration of the one or more substances is within a range of fromabout 2 atomic percent to about 20 atomic percent.
 5. The integratedstructure of claim 1 wherein said total concentration of the one or moresubstances is within a range of from about 6 atomic percent to about 11atomic percent.
 6. A method of forming an integrated structure,comprising: forming vertically-stacked conductive levels alternatingwith dielectric levels; forming vertically-stacked NAND memory cellsalong the conductive levels within a memory array region; forming astaircase region proximate the memory array region, the staircase regioncomprising electrical contacts in one-to-one correspondence with theconductive levels; forming a material over the memory array region andover the staircase region, the material being separated by an uppermostof the conductive levels by an intervening insulative material, thematerial being in direct physical contact with the interveninginsulative material; the material comprising silicon, nitrogen, and oneor more substances selected from the group consisting of carbon, oxygen,boron and phosphorus; forming an opening within the memory array regionextending through the material over the memory array region and throughat least some of the vertically-stacked conductive levels; and forming achannel material within the opening.
 7. The method of claim 6 whereinsaid total concentration of the one or more substances is within a rangeof from about 6 atomic percent to about 11 atomic percent.
 8. The methodof claim 6 wherein said one or more substances include carbon.
 9. Themethod of claim 8 wherein the material consists of silicon, nitrogen andcarbon.
 10. The method of claim 6 wherein said one or more substancesinclude oxygen.
 11. The method of claim 10 wherein the material consistsof silicon, nitrogen and oxygen.
 12. The method of claim 6 wherein saidone or more substances include boron.
 13. The method of claim 12 whereinthe material consists of silicon, nitrogen and boron.
 14. The method ofclaim 6 wherein said one or more substances include phosphorus.
 15. Themethod of claim 14 wherein the material consists of silicon, nitrogenand phosphorus.